2015—2020年江苏省戊型肝炎病毒流行病学特征及分子进化研究

Epidemiological characteristics and molecular evolution of hepatitis E virus in Jiangsu Province from 2015 to 2020

目的 研究近年江苏省人源与猪源戊型肝炎病毒(HEV)流行病学特征和分子进化特征。方法 对2015—2020年江苏省戊型肝炎病例特征进行描述性分析。收集南通如皋县、盐城东台市、淮安清浦区、无锡宜兴市4个监测点报告的戊型肝炎患者标本和当地猪胆汁标本,采用ELISA法进行HEV-IgM抗体检测,采用荧光定量PCR、巢式PCR对HEV RNA进行特异性扩增,阳性标本进行测序,所得基因序列开展进化分析,包括基因型及亚型分析、同源性分析等。结果 2015—2020年,江苏省共报告戊型肝炎病例15 955例,均为散发,年均发病率3.32/10万;报告2例死亡,病死率为1.25/万。下辖13个设区市中,病例数徐州市最多(占15.92%),常州市(占1.95%)最少;发病率南通市(4.96/10万)最高,无锡市(1.08/10万)最低,发病率差异有统计学意义(χ^(2)=75.89,P<0.01)。年均发病率男性(4.76/10万)高于女性(2.36/10万),差异有统计学意义(χ^(2)=7.35,P<0.01)。病例主要集中在40~59岁(占44.72%)和≥60岁(占41.16%)年龄组;职业主要为农民(占61.27%)。1—4月为发病主高峰(占41.25%),8月为次高峰(占8.37%)。共采集387份急性戊型肝炎病例血清样本和5 588份猪胆汁样本,得到109条人源HEV及78条猪源HEV序列,其中人源HEV均为基因4型,包含4种亚型;猪源HEV同样均为基因4型,包含2种亚型;人源与猪源HEV核苷酸序列的同源性范围为81%~100%。结论 江苏省近年基因4型HEV在戊肝患者中占绝对优势,人源与猪源HEV核苷酸序列高度同源,提示HEV有在人与猪之间传播的可能性。

Objective To study the epidemiological characteristics and molecular evolution characteristics of human and porcine hepatitis E virus(HEV) in Jiangsu Province in recent years. Methods A descriptive analysis was conducted on the characteristics of hepatitis E cases in Jiangsu Province from 2015 to 2020.Samples of hepatitis E patients and local pig bile samples reported from 4 monitoring sites in Rugao County, Yancheng Dongtai County, Huaian Qingpu District and Yixing City of Wuxi were collected.The HEV-IgM antibody was detected by ELISA,and the HEV RNA was specifically amplified by fluorescence quantitative PCR and nested PCR.The positive samples were sequenced.The obtained gene sequences were analyzed by evolutionary analysis, including genotype, subtype and homology analysis. Results From 2015 to 2020,a total of 15 955 cases of hepatitis E were reported in Jiangsu Province, all of which were sporadic patients, with an annual incidence of 3.32/10;.There were 2 death cases reported, with a fatality rate of 1.25/10;.The number of cases was the most in Xuzhou City(15.92%) and the least in Changzhou City(1.95%).The incidence rate was the highest in Nantong City(4.96/10;) and the lowest in Wuxi City(1.08/10;),and the difference was statistically significant(χ^(2)=75.89,P<0.01).The average annual incidence rate of male(4.76/10;) was higher than that of female(2.36/10;),and the difference was statistically significant(χ^(2)=7.35,P<0.01).The cases were mainly in the age group of 40-59 years(44.72%) and ≥60 years(41.16%).The main occupation was farmer(61.27%).The main incidence peak was from Jan to Apr(41.25%),and the secondary peak was Aug(8.37%).A total of 109 human HEV sequences and 78 pig HEV sequences were obtained from 387 acute hepatitis E case serum samples and 5 588 pig bile samples.The human HEV sequences were genotype 4,including 4 subtypes.Porcine HEV also belonged to genotype 4,including 2 subtypes.The homology of HEV nucleotide sequence from human and pig sources ranged from 81% to 100%. Conclusion HEV genotype 4 was dominant strain in HEV patients in Jiangsu Province in recent years.The nucleotide sequences of HEV from human and pig sources were highly homologous, suggesting the possibility of HEV transmission between human and pig.